East Coast Lows and Water Security

East coast lows (ECLs) can be damaging and costly storms, however they are also important for water security bringing the heavy soaking rainfall that fills dams along the coast and the Tablelands of New South Wales.

Research results

Regional water security over the east coast of NSW is significantly affected by ECL activity, with ECL types determining the timing, location and severity of effects.

The climate of the Eastern Seaboard of Australia is distinct from the rest of south eastern Australia, with little relationship between rainfall in this area and the major drivers of rainfall elsewhere in Australia, such as El Niño-Southern Oscillation.

However rainfall along the eastern seaboard is not homogenous with the region comprising 2-3 sub-regions with similar rainfall characteristics and where the location of ECL types and extent of their impacts are linked. This means that if ECL subtypes change in the future (due to either natural variability or climate change) then rainfall patterns will also change. For example rainfall events that we have relied on to fill reservoirs over the last 30-50 years may not occur or may occur outside of the reservoir catchments.

ESCCI-ECL Project Results

Most publicity about ECLs focuses on the negative and destructive aspects of these storms. But on the positive side ECLs and their associated rainfall are also important for generating significant inflows into major water storages along coastal NSW. This study aims to better understand the hydrologic importance of ECLs and related weather systems for water supply. This information will be used to better understand how water security may be affected if future climate change alters the frequency, intensity, duration and location of ECLs.

Characterisation of ECL sub-types and their relationship with large-scale drivers of hydroclimatic variability

5.2: Testing the hydrologic validity of downscaled climate data for water security assessment

Assessing the ability of using NARCliM data in modelling to replicate hydrology and persistence of runoff that is important in the performance of reservoir systems

5.3: Assessing the impact of ECLs on water security

Based on a series of case studies with different ECL impacts (North and South coast)

Evaluating how sensitive water resource systems are to changes in ECL behaviour

Research for Project 5 was initiated in 2013 and will be completed in 2016.

References

Chowdhury, A.F.M.K., Lockart, N., Willgoose, G., Kuczera, G. and Parana Manage, N. (2015): Development of a compound distribution Markov chain model for stochastic simulation of daily rainfall with long term variability. Water Resources Research, IN REVIEW.

Twomey, C. and Kiem, A.S. (2015): Spatial and temporal inhomogeneity of rainfall patterns in Australia - why is the eastern seaboard of Australian (ESA) different and why does inhomogeneity also exist within the ESA? International Journal of Climatology, IN REVIEW.

Twomey, C. and Kiem, A.S. (2015): East Coast Lows (ECLs) and rainfall along the eastern seaboard of Australia (ESA) - comparison of datasets used to record ECL occurrence and impacts on rainfall. Monthly Weather Review, IN PREPARATION.

Do you want to see how climate change will affect your region?

This site works best when viewed in a modern browser, for instance Internet Explorer 11 or latest versions of Google Chrome and Mozilla Firefox.

The Adapt NSW site now has an interactive map that allows you to see how climate change is projected to affect your region. You can look at the high resolution grid maps which display climate change at 10km scale or the regional maps which provide a summary for your region. Click through the variables and different time periods to see how the climate is projected to change for your region.

Are you looking for climate change data?

For the first time, the NSW and ACT Regional Climate Model (NARCLiM) allows you access to high resolution climate change data. This data is in a format that can be inputted directly into most biophysical models. You can choose the variable, time period and location of the data you want to download. The data portal provides instructions on how to download the data.

Do you want to learn more about climate change?

The About Climate Change tab provides a one stop shop for information on how and why our climate is changing. There is information to help understand the causes of climate change, climate change modelling, evidence of climate change today and how NSW is responding to the challenge.

Do you want to know how to adapt to climate change?

Climate change projections help us to understand how climate change is going to impact us. We then need to know how to adapt to those impacts. Adapting to climate change provides information on what adaptation is, sector specific issues and responses, and the process you can go through to understand and respond to the risks to and vulnerabilities of your services, assets and community from climate change.